An important departure from screw-type extruder machine for processing plastic and polymeric materials is the rotary processor described and claimed in the application of Zehev Tadmor, Ser. No. 795,211 filed May 11, 1977 (now U.S. Pat. No. 4,142,805) as a Continuation in Part of Application Ser. No. 654,040 filed Feb. 2, 1976 (now abandoned).
The machine of the Tadmor application includes one or more annular channels for rotation in close engagement with an annular housing which forms, with the channel, an enclosed passage. A channel block is disposed in the channel to hold material in the channel for movement relative to the channel surface when the annular channel is rotated so that the movement of the walls of the channel acts on material in the channel for processing such as melting or plasticating, conveying, pumping or pressurizing viscous liquid material, mixing, blending etc. The application discloses, as one modification, a machine in which processed material discharged from the outlet of one channel enters a conduit which conducts it around the outside of the housing and introduces it to the inlet of a succeeding processing channel.
It has been found however that frictional forces and heat losses involved in the use of such a conduit are undesirably high, that keeping the conduit clear and free from degraded material is difficult and that the complexity of the conduit arrangement raises the cost of the machine.